The Missing Link: A Case of Absent Pituitary Infundibulum and Ectopic Neurohypophysis in a Pediatric Patient with Heterotaxy Syndrome

Abstract

We report a case of absent pituitary infundibulum and ectopic neurohypophysis in a 4-year-old patient presenting clinically with hypopituitarism as well as heterotaxy syndrome complicated by global developmental delay and growth retardation. The clinical and laboratory workup of our patient suggested underlying hypopituitarism related to either congenital or acquired pathology, necessitating MRI to distinguish between them. We explain the various structural causes of hypopituitarism and detail how to predict the MRI findings and treatment, based on a fundamental understanding of the anatomy and pathophysiology of the hypothalamic pituitary axis and distinguishing anterior versus posterior pituitary hormone derangements. We also discuss two important theories widely acknowledged in the literature to explain congenital hypopituitarism: 1. Head trauma typically during birth resulting in a stretch injury to the infundibulum. 2. Congenital fetal maldevelopment of midline structures.

MRI of ectopic posterior pituitary gland with dysgenesis of pituitary stalk in a patient with hypogonadotropic hypogonadism

“…Breech deliveries, neonatal hypoxia, hypoglycemia and jaundice are important predisposing factors for EPP and stalk anomalies, due to ensuing neuronal reorganization of the proximal stump of the infundibulum [1] . Several genetic factors (PITI, PROPI, HES X1, LHX 3, LHX4, SOX3) have been attributed as influencing factors in this disease entity because these genes normally contribute to the development of hypothalamic–pituitary axis [8] . The literature review also suggests association of EPP with several congenital malformations that include septo-optic dysplasia, optic chiasm hypoplasia, holoprosencephaly, periventricular nodular heterotopia and absence of internal carotid artery [9] .…”

“…Our case, however lacked the characteristic clinical feature of smell disorder. Furthermore, pituitary–hypothalamic axis mass lesions such as pituitary macroadeoma, craniopharyngioma, congenital hamartomas and germinomas can present with secondary hypogonadotropic hypogonadism [4] , [8] , [9] , [10] . Hypogonadotropic hypogonadism can also be caused by various infiltrative conditions that include, sarcoidosis, lymphocytic hypophysitis and histiocytosis affecting the hypothalmo-pituitary axis [11] , [12] .…”

Cerebral Palsy and Heterotaxy Syndrome: A Case Report

“…Neurological abnormalities are not adequately reported in children with HS, however, some central nervous system (CNS) anomalies like hydrocephalus, absent corpus callosum, holonprosencephaly, meningomyelocoele and cerebral dysgenesis were reported and these conditions may give rise to CP [21]. Additionally, panhypopituitarism, absent pituitary infundibulum and ectopic neurohypophysis were also reported in literature [22]. In a study by Ticho and colleagues, midline central nervous system defects like meningomyelocele, porencephalic cyst, cerebellar agenesis, encephalocele, Dandy-Walker cyst, holoprosencephaly, diplomyelia, and hydromyelia were found in some patients with HS with some of them manifesting clinically as CP [23].…”